JONESBORO, Ark. (AP)  Arkansas State University students working on a video project sparked reports of armed men near the student union on Sunday, leading to a lockdown of about an hour at ASU’s Jonesboro campus.

The university sent an emergency alert shortly before 2 p.m. Sunday saying two armed men were seen near the student union. A later message said three men wearing all black were seen.

The university lifted the lockdown about an hour later after authorities determined there was no threat. Jonesboro police said costumed actors had been reported as possible armed intruders.

“Those students have been located and talked to,” Arkansas State spokesman Bill Smith told The Associated Press. “There was apparently no threat at all and no gunman.”

Arkansas State and Jonesboro police issued statements saying there were no injuries reported and no arrests.

“Obviously we encourage people, if they see something out of the ordinary, to say something. But if you are going to be doing something that might be construed as being out of the ordinary, that you probably need to check in with the university administration to let us know what you’re doing,” Smith said.

The lockdown was the second at the school in recent months. A man with a shotgun drove onto campus on Dec. 10. That incident ended peacefully as the man eventually surrendered.